This is a pretty sneaky virus, after reading all the reports, here is the part that answers your question:
Some notes about the virus...
...It copies itself into your Windows system directory as
[email protected].
...It also creates an entry in the Windows system registry.
...It includes it's own email program, so it will send the emails out to others without your seeing evidence of it in your email program.
...Some of the files it sends out may end up with double extensions.
...It takes email addresses both from your address book and from your temporary Internet files folder, so a lot of websites like TruthOrFiction.com are receiving the emails as well. TruthOrFiction.com has received hundreds of infected files in just a matter of hours, but our virus protection software has caught them all.
Jay